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Fořt J, Kunc B, Valentova JV, Bártová K, Hudáčová K. Examining the Fraternal Birth Order Effect and Sexual Orientation: Insights from an East European Population. ARCHIVES OF SEXUAL BEHAVIOR 2024; 53:2905-2922. [PMID: 38869747 PMCID: PMC11335834 DOI: 10.1007/s10508-024-02892-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/05/2024] [Accepted: 05/07/2024] [Indexed: 06/14/2024]
Abstract
The development of human sexual orientation remains a complex and multifaceted subject. It is often studied but its origins continue to elude us. In this preregistered study, our primary objective was to demonstrate the fraternal birth order effect (FBOE), which assumes a higher prevalence of older brothers in gay men than in their straight counterparts and which has also been recently recorded in lesbian women. Our second aim was to explore any potential impact of the FBOE on anal-erotic role orientation (AERO), both in gay and straight men. Our study sample included 693 gay men, 843 straight men, 265 lesbian women, and 331 straight women from Czechia and Slovakia. Employing a conventionally parameterized logistic regression model, we substantiated the FBOE among both gay men (OR = 1.35 for maternal older brothers) and lesbian women (OR = 1.71). These outcomes were confirmed by a more nuanced parameterization recently proposed by Blanchard (2022). Nonmaternal older brothers did not exhibit a significant influence on their younger brothers' sexual orientation. Contrary to some earlier reports, however, our data did not establish the FBOE as exclusive to gay men with the receptive AERO. Furthermore, our observations indicated a lower offspring count for mothers of gay men compared to mothers of straight men. Emphasizing the positive FBOE outcomes, we acknowledge the need for caution regarding the various options that can be used to estimate the familial influences on sexual orientation.
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Affiliation(s)
- Jakub Fořt
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 00, Prague, Czechia.
- Department of Psychology, Faculty of Arts, Charles University, Prague, Czechia.
| | - Benjamin Kunc
- Department of Neurosciences, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | | | - Klára Bártová
- Department of Psychology and Life Sciences, Faculty of Humanities, Charles University, Prague, Czechia
- National Institute of Mental Health, Klecany, Czechia
| | - Kateřina Hudáčová
- Department of Psychology, Faculty of Arts, Charles University, Prague, Czechia
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2
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Silva T. Self-Rated Masculinity and Femininity and Reported Number of Lifetime Sexual Partners Among Cisgender Heterosexual and LGBQ Men and Women. ARCHIVES OF SEXUAL BEHAVIOR 2024; 53:1633-1644. [PMID: 38097871 DOI: 10.1007/s10508-023-02756-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 11/18/2023] [Accepted: 11/20/2023] [Indexed: 05/21/2024]
Abstract
Prior research has quantitatively examined why heterosexual men and women report different numbers of lifetime different-sex sexual partners, whereas qualitative work has analyzed how men's masculinity-and to a lesser extent, women's femininity-is tied to gender norms about sexual activity. Less research, however, has quantitatively examined the associations between self-rated masculinity and femininity and reported number of lifetime sexual partners. This brief report uses a large sample of Canadians (n = 2117) to examine how self-rated masculinity and femininity relate to reported numbers of sexual partners among four groups of cisgender people: (1) heterosexual men (n = 972), (2) heterosexual women (n = 979), (3) gay and bisexual/pansexual men (n = 99), and (4) lesbian and bisexual/pansexual women (n = 67). Results demonstrate that self-rated femininity was negatively, and masculinity positively, associated with reported numbers of lifetime different-sex sexual partners among heterosexual women. No significant associations emerged for other groups. The lack of significant associations among heterosexual men may be attributable to the fact that most rated themselves as very masculine and not very feminine, whereas there was more variation among heterosexual women. In contrast, the non-significance among LGBQ women and men could reflect that subcultural norms and practices more strongly shape the number of sexual partners individuals report having in these communities. These results demonstrate that it would be beneficial for researchers to measure self-rated masculinity and femininity in future studies about sexual partnering practices, especially among heterosexual cisgender women.
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Affiliation(s)
- Tony Silva
- Department of Sociology, University of British Columbia, 6303 NW Marine Drive, Vancouver, BC, V6T 1Z1, Canada.
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3
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Sadr-Bazzaz M, Talaei A, Sadeghi MJ, Moradi M, Ahmadisoleymani Z, Vasey PL. Association of Recalled Childhood Sex-Typed Behavior with Sexual Orientation and Gender Identity in Iranian Adult Males and Females. JOURNAL OF SEX RESEARCH 2024:1-14. [PMID: 38691343 DOI: 10.1080/00224499.2024.2346926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Same-sex sexual attraction in both males and females has been associated with childhood sex-atypical behavior. Gynephilic females recall behaving in a manner that is less female-typical and more male-typical compared to cisgender androphilic females, whereas androphilic males recall behaving in a manner that is less male-typical and more female-typical compared to cisgender gynephilic males. In addition, male and female ambiphilic individuals exhibit intermediate levels of childhood sex-atypicality. In this study, we examined recalled childhood sex-typed behavior among Iranian cisgender gynephilic males (n = 236), cisgender ambiphilic males (n = 51), cisgender androphilic males (n = 191), transgender androphilic males (n = 60), cisgender androphilic females (n = 243), cisgender ambiphilic females (n = 96), cisgender gynephilic females (n = 32), and transgender gynephilic females (n = 122). Both cisgender androphilic males and cisgender gynephilic females recalled elevated childhood sex-atypicality, scoring intermediate between cisgender gynephilic males and cisgender androphilic females. Male and female ambiphilic participants scored intermediate between their other- and same-sex attracted cisgender counterparts. Transgender androphilic males exhibited hyper-feminized childhood behavior, scoring even more female-typical than cisgender androphilic females. Transgender gynephilic females recalled behaving as male-typical as cisgender gynephilic males. Consistent with previous research, our findings from Iran - a non-Western, Middle Eastern culture - provide cross-cultural support for the universality of childhood sex-atypicality as a normative developmental precursor of monosexual or ambisexual same-sex attraction in both males and females who are cisgender and transgender.
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Affiliation(s)
| | - Ali Talaei
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences
| | | | - Marjan Moradi
- Department of Psychology, Toos Institute of Higher Education
| | | | - Paul L Vasey
- Department of Neuroscience, University of Lethbridge
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4
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Burke FF, Hinks M, Salia S, Sparkes KM, Swift-Gallant A. Using Animal Models to Study the Interplay Between the Biodevelopmental Pathways Underlying Human Sexual Orientation. ARCHIVES OF SEXUAL BEHAVIOR 2023; 52:2979-2984. [PMID: 36477673 DOI: 10.1007/s10508-022-02499-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Affiliation(s)
- Francine F Burke
- Department of Psychology, Memorial University of Newfoundland, 230 Elizabeth Ave., St John's, NL, A1B 3X9, Canada
| | - Meagan Hinks
- Department of Psychology, Memorial University of Newfoundland, 230 Elizabeth Ave., St John's, NL, A1B 3X9, Canada
| | - Stephanie Salia
- Department of Psychology, Memorial University of Newfoundland, 230 Elizabeth Ave., St John's, NL, A1B 3X9, Canada
| | - Kerri M Sparkes
- Department of Psychology, Memorial University of Newfoundland, 230 Elizabeth Ave., St John's, NL, A1B 3X9, Canada
| | - Ashlyn Swift-Gallant
- Department of Psychology, Memorial University of Newfoundland, 230 Elizabeth Ave., St John's, NL, A1B 3X9, Canada.
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5
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Balthazart J, Roselli CE. Hormonal, Genetic, Immunological: An Array of Mechanisms but How Do They Interact, If at All? ARCHIVES OF SEXUAL BEHAVIOR 2023; 52:2963-2971. [PMID: 36376746 DOI: 10.1007/s10508-022-02469-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 05/20/2023]
Affiliation(s)
| | - Charles E Roselli
- Department of Chemical, Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
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6
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VanderLaan DP, Skorska MN, Peragine DE, Coome LA. Carving the Biodevelopment of Same-Sex Sexual Orientation at Its Joints. ARCHIVES OF SEXUAL BEHAVIOR 2023; 52:2939-2962. [PMID: 35960401 DOI: 10.1007/s10508-022-02360-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/30/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
Sexual orientation is a core aspect of human experience and understanding its development is fundamental to psychology as a scientific discipline. Biological perspectives have played an important role in uncovering the processes that contribute to sexual orientation development. Research in this field has relied on a variety of populations, including community, clinical, and cross-cultural samples, and has commonly focused on female gynephilia (i.e., female sexual attraction to adult females) and male androphilia (i.e., male sexual attraction to adult males). Genetic, hormonal, and immunological processes all appear to influence sexual orientation. Consistent with biological perspectives, there are sexual orientation differences in brain development and evidence indicates that similar biological influences apply across cultures. An outstanding question in the field is whether the hypothesized biological influences are all part of the same process or represent different developmental pathways leading to same-sex sexual orientation. Some studies indicate that same-sex sexually oriented people can be divided into subgroups who likely experienced different biological influences. Consideration of gender expression in addition to sexual orientation might help delineate such subgroups. Thus, future research on the possible existence of such subgroups could prove to be valuable for uncovering the biological development of sexual orientation. Recommendations for such future research are discussed.
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Affiliation(s)
- Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada.
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Malvina N Skorska
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Diana E Peragine
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
| | - Lindsay A Coome
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
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7
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Vilsmeier JK, Kossmeier M, Voracek M, Tran US. The fraternal birth-order effect as a statistical artefact: convergent evidence from probability calculus, simulated data, and multiverse meta-analysis. PeerJ 2023; 11:e15623. [PMID: 37609443 PMCID: PMC10441532 DOI: 10.7717/peerj.15623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 06/01/2023] [Indexed: 08/24/2023] Open
Abstract
The fraternal-birth order effect (FBOE) is a research claim which states that each older brother increases the odds of homosexual orientation in men via an immunoreactivity process known as the maternal immune hypothesis. Importantly, older sisters supposedly either do not affect these odds, or affect them to a lesser extent. Consequently, the fraternal birth-order effect predicts that the association between the number of older brothers and homosexual orientation in men is greater in magnitude than any association between the number of older sisters and homosexual orientation. This difference in magnitude represents the main theoretical estimand of the FBOE. In addition, no comparable effects should be observable among homosexual vs heterosexual women. Here, we triangulate the empirical foundations of the FBOE from three distinct, informative perspectives, complementing each other: first, drawing on basic probability calculus, we deduce mathematically that the body of statistical evidence used to make inferences about the main theoretical estimand of the FBOE rests on incorrect statistical reasoning. In particular, we show that throughout the literature researchers ascribe to the false assumptions that effects of family size should be adjusted for and that this could be achieved through the use of ratio variables. Second, using a data-simulation approach, we demonstrate that by using currently recommended statistical practices, researchers are bound to frequently draw incorrect conclusions. And third, we re-examine the empirical evidence of the fraternal birth-order effect in men and women by using a novel specification-curve and multiverse approach to meta-analysis (64 male and 17 female samples, N = 2,778,998). When analyzed correctly, the specific association between the number of older brothers and homosexual orientation is small, heterogenous in magnitude, and apparently not specific to men. In addition, existing research evidence seems to be exaggerated by small-study effects.
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Affiliation(s)
- Johannes K. Vilsmeier
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Michael Kossmeier
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Martin Voracek
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Ulrich S. Tran
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
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8
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Blanchard R, Skorska MN. New Data on Birth Order in Homosexual Men and Women and a Reply to Vilsmeier et al. (2021a, 2021b). ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:3319-3349. [PMID: 35713755 DOI: 10.1007/s10508-022-02362-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
The fraternal birth order effect (FBOE) is the repeated finding that older brothers increase the odds of homosexuality in later-born males. It has been our working assumption, based on the majority of previous studies, that a similar FBOE does not occur in females. In an elaborate quantitative review posted last year to a preprint server, Vilsmeier et al. (2021a) concluded that there is no valid evidence for an FBOE in men or women. Ablaza et al. (2022) subsequently published a study of population-level data from the Netherlands with conclusions completely opposite to those of Vilsmeier et al., namely, that there is robust evidence of an FBOE in both men and women. The present research was initially undertaken to refute the assertion of Vilsmeier et al. that there is no proof of an FBOE in men and to investigate how they obtained such a discrepant conclusion. We found evidence that the discrepancy may relate to Vilsmeier et al.'s use of the large and demonstrably unreliable sample published by Frisch and Hviid (2006). After the publication by Ablaza et al., we expanded our article to address their finding of an FBOE in women. We argue that our preferred explanation of the FBOE in men-that it reflects the progressive immunization of some mothers to Y-linked antigen by each succeeding male fetus and the concomitantly increasing effects of anti-male antibody on sexual differentiation in the brain in each succeeding male fetus-could plausibly be extended to female homosexuality.
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Affiliation(s)
- Ray Blanchard
- Department of Psychiatry, University of Toronto, Toronto, ON, M5T 1R8, Canada.
| | - Malvina N Skorska
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
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9
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Silva T. Subcultural Identification, Penetration Practices, Masculinity, and Gender Labels within a Nationally Representative Sample of Three Cohorts of American Black, White, and Latina/o LGBQ People. ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:3467-3483. [PMID: 35997907 DOI: 10.1007/s10508-022-02285-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 06/15/2023]
Abstract
Most quantitative research about lesbian, gay, bisexual, and queer (LGBQ) people's sexual subcultures and sexual practices has used non-probability samples due to data limitations. This paper used the Generations study, a national probability sample of LGBQ Americans in three age cohorts, 18-25 (n = 510), 34-41 (n = 294), and 52-59 (n = 425), who also identified as Black, white, or Latina/o. This paper analyzed men (n = 590) and women (n = 639) to answer the following sets of research questions: (1) What is the prevalence of subcultural identification as bear, leather/kink, twink, and jock among men, and how does it differ by cohort, race/ethnicity, and sexual identity? (2) What is the prevalence of men who describe themselves as a top, versatile top, versatile, versatile bottom, and bottom? What is the relationship between penetration practices and masculinity? (3) What is the prevalence of gender labels among women as femme, androgynous, and butch? How does the prevalence differ by cohort, race/ethnicity, and sexual identity? (4) What is the relationship between women's gender labels and masculinity? Penetration practices were fairly evenly distributed among men, and there were few differences in masculinity based on penetration practices after controlling for demographics and subcultural identification. Most women did not use gender labels, but butch identities were more common among lesbians and femme labels were more common among Black women and Latinas.
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Affiliation(s)
- Tony Silva
- Department of Sociology, University of British Columbia, 6303 NW Marine Drive, Vancouver, BC, V6T 1Z1, Canada.
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10
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Swift-Gallant A, Shirazi T, Puts DA, Breedlove SM. Evidence for Perinatal Steroid Influence on Human Sexual Orientation and Gendered Behavior. Cold Spring Harb Perspect Biol 2022; 14:a039123. [PMID: 34872968 PMCID: PMC9341466 DOI: 10.1101/cshperspect.a039123] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In laboratory animals, exposure to gonadal steroid hormones before and immediately after birth can exert permanent effects on many behaviors, particularly reproductive behaviors. The extent to which such effects occur in humans remains an open question, but several lines of evidence indicate that perinatal levels of both androgens and estrogens may affect adult human psychology and behavior, including sexual orientation and gender nonconformity. Some putative indicators of prenatal androgen exposure, including the ratio of the length of the index finger to that of the ring finger (2D:4D), have repeatedly indicated that lesbians, on average, were exposed to more prenatal androgens than straight women, suggesting that sufficient fetal androgen exposure predisposes a fetus to gynephilia (attraction to women) at maturity. The digit ratios of gay men do not differ from those of straight men, suggesting that prenatal androgen levels are not responsible for their androphilia (attraction to men). However, evidence that gay men who prefer an insertive anal sex role (ASR) have more masculine digit ratios than those preferring a receptive ASR suggests that early androgens influence some sexual preferences in men. Furthermore, digit ratios among gay men have been found to correlate with recalled childhood gender nonconformity (CGN). People with isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) offer further insight into the effects of perinatal gonadal steroid exposure. In people with IGD, gonadal hormone production is low or absent after the first trimester of gestation. However, because placental gonadotropins drive gonadal hormone secretion during the first trimester when genitalia sexually differentiate, individuals with IGD are unambiguously male or female at birth, consistent with their chromosomal and gonadal sex. Men with IGD report greater CGN, again suggesting that perinatal androgen exposure contributes to male-typical behavioral patterns in humans. Interestingly, women with IGD report less androphilia and more bisexuality than control women, suggesting that perinatal ovarian steroids in females typically augment androphilia in adulthood. Taken together, these findings indicate that the perinatal hormonal milieu influences human sexual orientation and gender conformity.
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Affiliation(s)
- Ashlyn Swift-Gallant
- Department of Psychology, Memorial University of Newfoundland, St. John's A1B 3X9, Newfoundland and Labrador
| | - Talia Shirazi
- Department of Anthropology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - David A Puts
- Department of Anthropology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - S Marc Breedlove
- Neuroscience Program, Michigan State University, East Lansing, Michigan 48824, USA
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11
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Moskowitz DA, Alvarado Avila A, Kraus A, Birnholtz J, Macapagal K. Top, Bottom, and Versatile Orientations among Adolescent Sexual Minority Men. JOURNAL OF SEX RESEARCH 2022; 59:643-651. [PMID: 34309441 DOI: 10.1080/00224499.2021.1954583] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Sexual role preference or self-label (i.e., top, versatile, or bottom) has been well studied in samples of sexual minority men (SMM) but lacks research among adolescent sexual minority men (ASMM). In response, data were collected from 302 ASMM (15-18 years old), measuring sexual self-label, relationship and sexual experience, sexually explicit media use, use of geosocial networking applications, penis size satisfaction, and gender atypicality. Results showed there was no significant difference in the distribution of sexual position self-identity in ASMM when compared with data from published, adult samples. A model that associated sexual socialization factors with adopting any self-label was significant, with greater number of partners, previous geosocial networking app use, and more relationship experience being positive predictors of having a label. Additionally, a model that tested the convergent validity between self-label and enacted sexual behaviors was significant. Both receptive and insertive sex enactments were highly correlated with corresponding labels. Lastly, gender atypicality and penis size satisfaction were significant predictors of sexual position self-identity. Data from our study supports sexual self-labeling occurring before adulthood, during adolescence for SMM. Furthermore, it shows that socialization factors (e.g., partner frequency, using apps) are important in the development of sexual position self-identity in this population.
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Affiliation(s)
| | - Andrés Alvarado Avila
- Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University
| | - Ashley Kraus
- Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University
- Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine
| | - Jeremy Birnholtz
- Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University
- Department of Communication Studies, Northwestern University
| | - Kathryn Macapagal
- Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University
- Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine
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12
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Swift-Gallant A, Coome LA, Monks DA, VanderLaan DP. Recalled Childhood Separation Anxiety Differs by Anal Sex Role among Gay Men. JOURNAL OF SEX RESEARCH 2022; 59:546-554. [PMID: 33821703 DOI: 10.1080/00224499.2021.1903378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Male androphilia (i.e., male sexual attraction to adult males) is considered an evolutionary paradox because it is partially influenced by genes and associated with decreased reproduction. Traits associated with attachment to genetic relatives (i.e., kin) could prompt increased kin-directed altruism, thereby offsetting decreased reproduction by helping kin reproduce. These traits include childhood separation anxiety and adulthood neuroticism, which have been associated with feminine gender expression. In prior research, gay men with a receptive (Bottom or Versatile) anal sex role (ASR) reported greater childhood gender nonconformity (GNC) than those with an insertive (Top) ASR. We examined whether ASR groups also differed on recalled childhood separation anxiety and adulthood neuroticism. The Separation Anxiety Scale-Revised and Big-Five Personality Inventory - short form were completed by 350 gay and 146 heterosexual men. For neuroticism, ASR preference groups differed from heterosexual men but not from one another. Gay men who preferred a Bottom or Versatile ASR reported higher recalled childhood separation anxiety than Tops and heterosexual men. Recalled childhood GNC mediated ASR group differences with heterosexual men on childhood separation anxiety. These results indicate that subgroups of gay men delineated by ASR differ on an evolutionarily relevant developmental trait, childhood separation anxiety.
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Affiliation(s)
- Ashlyn Swift-Gallant
- Department of Psychology, University of Toronto Mississauga
- Department of Psychology, Memorial University of Newfoundland
| | | | - D Ashley Monks
- Department of Psychology, University of Toronto Mississauga
- Department of Cells and Systems Biology, University of Toronto
| | - Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga
- Child and Youth Psychiatry, Centre for Addiction and Mental Health
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13
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Differences in digit ratios between gay men who prefer receptive versus insertive sex roles indicate a role for prenatal androgen. Sci Rep 2021; 11:8102. [PMID: 33854100 PMCID: PMC8046970 DOI: 10.1038/s41598-021-87338-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
Among non-human mammals, exposure to androgens during critical periods of development leads to gynephilia (attraction to females), whereas the absence or low levels of prenatal androgens leads to androphilia (attraction to males). However, in humans, retrospective markers of prenatal androgens have only been associated with gynephilia among women, but not with androphilia among men. Here, we asked whether an indirect indication of prenatal androgen exposure, 2D:4D, differs between subsets of gay men delineated by anal sex role (ASR). ASR was used as a proxy for subgroups because ASR groups tend to differ in other measures affected by brain sexual differentiation, such as gender conformity. First, we replicated the finding that gay men with a receptive ASR preference (bottoms) report greater gender nonconformity (GNC) compared to gay men with an insertive ASR preference (tops). We then found that Tops have a lower (male-typical) average right-hand digit ratio than Bottoms, and that among all gay men the right-hand 2D:4D correlated with GNC, indicating that a higher (female-typical) 2D:4D is associated with increased GNC. Differences were found between non-exclusive and exclusive same-sex attraction and GNC, and ASR group differences on digit ratios do not reach significance when all non-heterosexual men are included in the analyses, suggesting greater heterogeneity in the development of non-exclusive same-sex sexual orientations. Overall, results support a role for prenatal androgens, as approximated by digit ratios, in influencing the sexual orientation and GNC of a subset of gay men.
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14
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Sternin S, McKie RM, Winberg C, Travers RN, Humphreys TP, Reissing ED. Sexual consent: Exploring the perceptions of heterosexual and non-heterosexual men. PSYCHOLOGY & SEXUALITY 2021. [DOI: 10.1080/19419899.2021.1879911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
| | | | | | - Robb N. Travers
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, Canada
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15
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Skorska MN, Coome LA, Saokhieo P, Kaewthip O, Chariyalertsak S, VanderLaan DP. Handedness and Birth Order Among Heterosexual Men, Gay Men, and Sao Praphet Song in Northern Thailand. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:2431-2448. [PMID: 32623540 DOI: 10.1007/s10508-020-01774-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Previous research has examined handedness and birth order to inform sexual orientation and gender identity/role expression development; however, sexual orientation and gender identity/role expression have rarely been disentangled to provide a more nuanced perspective. In Thailand, we investigated sexual orientation and gender identity simultaneously via comparison of 282 heterosexual men, 201 gay men, and 178 sao praphet song-i.e., androphilic, markedly feminine males recognized as a "third" gender. Handedness was examined as: extremely left-handed, moderately left-handed, ambidextrous, moderately right-handed, or extremely right-handed. Birth order was examined as numbers of older and younger brothers and sisters, by using Berglin's, fraternal, and sororal indices, and by examining the older brother odds ratio and sibling sex ratio. Compared with heterosexual men, gay men and sao praphet song were more likely to be extremely right-handed. Sao praphet song were also more likely to be extremely left-handed than heterosexual and gay men. Heterosexual men and sao praphet song had later sororal birth order compared with the expected Thai population value, suggesting stopping rules influenced when probands' mothers ceased having children. These findings provide new insights and replicate previous findings in a non-Western sample. Regarding handedness, in males, mechanisms related to extreme right-handedness likely influence the development of androphilia, whereas mechanisms related to both extreme right- and extreme left-handedness likely explain the combination of androphilia and feminine gender identity/role expression. Regarding birth order, similar to the conclusions of some prior research, stopping rules pose a challenge for testing the fraternal birth order effect.
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Affiliation(s)
- Malvina N Skorska
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
| | - Lindsay A Coome
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada
| | - Pongpun Saokhieo
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Oranitcha Kaewthip
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Suwat Chariyalertsak
- Research Institute of Health Sciences, Chiang Mai University, Chiang Mai, Thailand
- Faculty of Public Health, Chiang Mai University, Chiang Mai, Thailand
| | - Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada.
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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16
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Gómez Jiménez FR, Semenyna SW, Vasey PL. The relationship between fraternal birth order and childhood sex‐atypical behavior among the Istmo Zapotec
muxes. Dev Psychobiol 2020; 62:792-803. [DOI: 10.1002/dev.21987] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/22/2022]
Affiliation(s)
| | - Scott W. Semenyna
- Department of Psychology University of Lethbridge Lethbridge Alberta Canada
| | - Paul L. Vasey
- Department of Psychology University of Lethbridge Lethbridge Alberta Canada
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17
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Skorska MN, Bogaert AF. Fraternal Birth Order, Only-Child Status, and Sibling Sex Ratio Related to Sexual Orientation in the Add Health Data: A Re-analysis and Extended Findings. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:557-573. [PMID: 31802291 PMCID: PMC8241527 DOI: 10.1007/s10508-019-01496-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 05/18/2023]
Abstract
The fraternal birth order (FBO) effect related to men's sexual orientation refers to the finding that the number of older brothers that a man has increases his chance of being androphilic. The FBO effect has generally been well replicated in diverse samples; one instance of non-replication was by Francis (2008) using Waves I and III of the Add Health data. We attempted to replicate the FBO effect in the Add Health data taking into account family size and other limitations of Francis' (2008) analyses. Also, we examined other sibling characteristics related to the FBO effect: sibling sex ratio and only-child status. We used two subsamples from Waves I (n = 20,745) and IV (n = 15,701) of the Add Health data, consisting of adolescents who were followed longitudinally from 1994 to 1995 until 2008. Wave I data were used to compute numbers of younger and older brothers and sisters from household roster information. Wave IV information about sexual orientation identity was used. Analyses were conducted within men and within women. We found modest support for the FBO effect in men, but not in women, using the older brother odds ratio, logistic regression analyses, and sibling sex ratio, which provided the strongest support for FBO. We found that gynephilic/biphilic women, but not androphilic/biphilic men, were more likely to be only-children compared to androphilic women and gynephilic men, respectively. We discuss limitations of the Add Health data and purported mechanisms for the FBO effect in men and the only-child effect in women.
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Affiliation(s)
- Malvina N Skorska
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, ON, L5L 1C6, Canada.
- Department of Psychology, Brock University, St. Catharines, ON, Canada.
| | - Anthony F Bogaert
- Department of Psychology, Brock University, St. Catharines, ON, Canada
- Department of Health Sciences, Brock University, St. Catharines, ON, Canada
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18
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Nila S, Crochet PA, Barthes J, Rianti P, Juliandi B, Suryobroto B, Raymond M. Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia. EVOLUTIONARY PSYCHOLOGY 2019; 17:1474704919880701. [PMID: 31742436 PMCID: PMC10358421 DOI: 10.1177/1474704919880701] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/13/2019] [Indexed: 09/09/2023] Open
Abstract
Male homosexual preference (MHP) is an evolutionary enigma because it is partially heritable and imposes a fertility cost. In occidental societies, homosexual men are feminized at various levels and they have more older brothers than heterosexual men. To evaluate whether femininity and the fraternal birth order (FBO) effect are universal features of MHP or not, we collected original data from homosexual men, heterosexual men, and heterosexual women from Java (Indonesia). Facial photographs were used to test whether homosexual faces are feminized when compared with heterosexual ones. We found that faces manipulated to resemble the average face of homosexual men are perceived as facially feminized, suggesting that homosexual men are facially feminized compared to heterosexual men, although a higher facial femininity was not captured by morphological analyses. Then, family data were used to detect differences in siblings' composition between homosexuals and heterosexuals. Homosexual men displayed a higher number of older brothers than heterosexual men, even when sibship size was controlled for, suggesting that the FBO effect exists in Indonesian populations. Independent of sexual orientation, men with older brothers seem more feminized than those without older brothers, consistent with the immune origin of the FBO effect. In conclusion, MHP in Indonesia is partially feminized and they have more older brothers. Such features are also associated with MHP in other cultural contexts, suggesting a cross-cultural effect of men homosexual preference. An evolutionary explanation is available for the feminizing effect, although the FBO effect remains unexplained even if proximal mechanisms start to be identified.
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Affiliation(s)
- Sarah Nila
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia
| | - Pierre-Andre Crochet
- CEFE, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, France
| | - Julien Barthes
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, France
| | - Puji Rianti
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia
| | - Berry Juliandi
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia
| | - Bambang Suryobroto
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia
| | - Michel Raymond
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, France
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19
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Moskowitz DA, Garcia CP. Top, Bottom, and Versatile Anal Sex Roles in Same-Sex Male Relationships: Implications for Relationship and Sexual Satisfaction. ARCHIVES OF SEXUAL BEHAVIOR 2019; 48:1217-1225. [PMID: 29858726 DOI: 10.1007/s10508-018-1240-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 02/17/2018] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
Across much of the gay and bisexual male research on sexual position self-label (i.e., calling oneself a top, bottom, or versatile), there exist two commonalities: (1) studies tend to focus almost entirely on individual, relationally single androphilic men; (2) studies rarely account for relationships and relationship dynamics. In response, we explored the role of self-label over sexual and relationship satisfaction among gay and bisexual partnered men. Specifically, we looked at whether adopted sexual position identities were consonant or dissonant (i.e., matching or mismatching) with enacted behavior in relationships and how that impacted men's attitudes toward different relational attributes. Through an online survey, we sampled 169 men in same-sex relationships, asking them questions about their ideal penetrative role identities and their reality penetrative roles with their partner. We then asked them to rate their relationship on 10 sexual and interpersonal attributes. Multiple regression modeling suggested ideal-reality penetrative role dissonance was predictive of sexual dissatisfaction among tops who bottomed in their relationships and, to a lesser extent, bottoms who topped. In contrast, penetrative role dissonance was predictive of relationship satisfaction among tops who bottomed in their relationship, but not bottoms who topped. We conclude that a potential reason for this paradox among tops who bottom may be sexual altruism. That is, men may be satisfied with other aspects within their relationships, understand their partner's anal sex preferences, and accommodate that position in response to their initial relationship satisfaction.
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Affiliation(s)
- David A Moskowitz
- Department of Medical Social Sciences, Feinberg School of Medicine, Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University, 625 N. Michigan Ave., Ste. 14-051, Chicago, IL, 60611, USA.
| | - Christopher P Garcia
- Department of Medical Social Sciences, Feinberg School of Medicine, Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University, 625 N. Michigan Ave., Ste. 14-051, Chicago, IL, 60611, USA
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20
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Wampold CH. The Association Between Fraternal Birth Order and Anal-Erotic Roles of Men Who Have Sex with Men. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:2445-2454. [PMID: 29956083 DOI: 10.1007/s10508-018-1237-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 03/06/2018] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
The fraternal birth order effect (FBOE) describes the phenomenon that homosexual men tend to have a greater number of older brothers than do heterosexual men. The FBOE is a marker for an innate, biological predisposition for androphilia in genotypic males. The FBOE has been studied since the 1930s and is the most consistent biodemographic correlate of sexual orientation in men. This study sought to determine whether the FBOE applies equally to all men who have sex with men (MSM), or disproportionately to MSM whose anal intercourse behavior is predominantly receptive (Bottoms). Participants included 243 North American adult MSM who responded to advertisements posted on a Web site and other electronic media associated with the GALA festival, a quadrennial gathering of gay and lesbian choruses. Each was asked whether his anal intercourse behavior during the preceding year was predominantly receptive, predominantly penetrative, or about equally receptive and penetrative. Those who indicated their behavior was predominantly receptive were coded "Bottoms"; all others were coded "Not-Bottoms." Participants were also surveyed as to their sibship composition. Bottoms had a significantly greater mean number of older brothers than did Not-Bottoms. There was no significant difference with respect to older or younger sisters or younger brothers. Further, the older sibling sex ratio (OSSR) for the Bottom cohort, but not for the Not-Bottom cohort, was significantly higher than the expected OSSR for the general male population (OSSR = No. older brothers/No. older sisters × 100; expected OSSR for general population = 106). Thus, late fraternal birth order was correlated with receptive anal-erotic behavior among MSM.
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Affiliation(s)
- Charles H Wampold
- Collaborative Research Group on Health Policy and Promotion + UrbanHealth Lab, York College of the City University of New York, Jamaica, NY, USA.
- , 41 South Harrison Street, Princeton, NJ, 08540, USA.
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21
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Coome LA, Skorska MN, van der Miesen AI, Peragine DE, VanderLaan DP. An examination of the biodevelopment of gender expression in children ages 6- to 12-years. CANADIAN JOURNAL OF HUMAN SEXUALITY 2018. [DOI: 10.3138/cjhs.2018-0013] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Lindsay A. Coome
- Department of Psychology, University of Toronto, Mississauga, ON
| | | | - Anna I.R. van der Miesen
- Center of Expertise on Gender Dysphoria, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Doug P. VanderLaan
- Department of Psychology, University of Toronto, Mississauga, ON
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON
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22
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Blanchard R. Fraternal Birth Order, Family Size, and Male Homosexuality: Meta-Analysis of Studies Spanning 25 Years. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:1-15. [PMID: 28608293 DOI: 10.1007/s10508-017-1007-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/15/2017] [Accepted: 05/22/2017] [Indexed: 06/07/2023]
Abstract
The fraternal birth order effect is the tendency for older brothers to increase the odds of homosexuality in later-born males. This study compared the strength of the effect in subjects from small versus large families and in homosexual subjects with masculine versus feminine gender identities. Meta-analyses were conducted on 30 homosexual and 30 heterosexual groups from 26 studies, totaling 7140 homosexual and 12,837 heterosexual males. The magnitude of the fraternal birth order effect was measured with a novel variable, the Older Brothers Odds Ratio, computed as (homosexuals' older brothers ÷ homosexuals' other siblings) ÷ (heterosexuals' older brothers ÷ heterosexuals' other siblings), where other siblings = older sisters + younger brothers + younger sisters. An Older Brothers Odds Ratio of 1.00 represents no effect of sexual orientation; values over 1.00 are positive evidence for the fraternal birth order effect. Evidence for the reliability of the effect was consistent. The Older Brothers Odds Ratio was significantly >1.00 in 20 instances, >1.00 although not significantly in nine instances, and nonsignificantly <1.00 in 1 instance. The pooled Older Brothers Odds Ratio for all samples was 1.47, p < .00001. Subgroups analyses showed that the magnitude of the effect was significantly greater in the 12 feminine or transgender homosexual groups than in the other 18 homosexual groups. There was no evidence that the magnitude of the effect differs according to family size.
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Affiliation(s)
- Ray Blanchard
- Department of Psychiatry, University of Toronto, Toronto, ON, M5T 1R8, Canada.
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23
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Wampold CH. Volvivity, Femininity, Fraternity: Breaching the Sexual Orientation Fortress. ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:43-46. [PMID: 29071545 DOI: 10.1007/s10508-017-1101-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/11/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Charles H Wampold
- Collaborative Research Group on Health Policy and Promotion, York College of the City University of New York, Jamaica, NY, USA.
- , 41 South Harrison Street, Princeton, NJ, 08540, USA.
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24
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Bartlett NT, Hurd PL. Fraternal Birth Order Effects on Personality: Will Reasonable Claims Require Extraordinary Evidence? ARCHIVES OF SEXUAL BEHAVIOR 2018; 47:21-25. [PMID: 29098453 DOI: 10.1007/s10508-017-1109-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Nathan T Bartlett
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, AB, T6G 2E9, Canada.
- School of Public Health, University of Alberta, Edmonton, AB, Canada.
| | - Peter L Hurd
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, AB, T6G 2E9, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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25
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Breedlove SM. Response to Commentaries. ARCHIVES OF SEXUAL BEHAVIOR 2017; 46:1625-1629. [PMID: 28741047 DOI: 10.1007/s10508-017-1034-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/06/2017] [Indexed: 06/07/2023]
Affiliation(s)
- S Marc Breedlove
- Neuroscience Program, Departments of Psychology, Integrative Biology, Michigan State University, 293 Farm Lane, Giltner Hall, Room 108, East Lansing, MI, 48824, USA.
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